1. Field of the Invention
The present invention relates to a flexible hose for a vacuum cleaner, in which a long extrusion molding band is wound in a cylindrical form, and a fabricating method thereof, and more particularly, to a flexible hose for a vacuum cleaner, in which a multi-band extrusion molding is employed such that a plurality of extrusion molding bands are arranged in parallel and connected to one another, wound in a cylindrical form, and a fabricating method thereof is also included.
2. Description of the Prior Art
A flexible hose for a vacuum cleaner is made cylindrically by winding an extrusion molding band, which is extrusion-molded in a single line. The cross-section of the extrusion molding band may include a wave shape ‘’. One side of the cross-section may include an electric wire embedding portion and the other side may include a semicircle portion having a semicircle shape. When the extrusion molding band is wound in a cylindrical form so as to fabricate the flexible hose, the semicircle portion of the other side is folded on the electric wire embedding a portion of the one side and attaching to the electric wire embedding portion by an adhesive. Accordingly, the conventional flexible hose is made by bonding two lines of extrusion molding bands with an adhesive and winding the two lines of bonded and folded extrusion molding bands at the same time.
In other words, to fabricate a flexible hose of an extrusion molding having two bands, four extrusion motors (two motors for extruding extrusion molding bands and two bonding motors) are employed. The fabricating method includes the steps of cooling a first extrusion molding band molded out from a first extruder along with an embedded electric wire, fixing the first extrusion molding band dimensionally with a sizing mold simultaneously, drawing the first extrusion molding band with a cooling drawer, ascertaining the size of the first extrusion molding band, repeating the above-mentioned steps by operating a second extruder if the size is satisfactory, bonding the two extrusion molding bands by a first bonder if the extrusion molding bands have no problem in their shape, winding the two extrusion molding bands with a predetermined angle and bonding the two extrusion molding bands at the winding starting portions by using a second bonder simultaneously.
Alternatively, to fabricate a flexible hose with three lines of extrusion molding bands, six extrusion motors (two motors for extruding extrusion molding bands and two bonding motors) and three or four electric wires are needed. When using four electric wires, a danger of a short circuit may occur because two electric wires are inserted into any one of the three lines of extrusion molding bands. In this case, the fabrication method includes the steps of: cooling a first extrusion molding band molded out from a first extruder with an embedded electric wire and at the same time fixing the size of the first extrusion molding band using a sizing mold; drawing the first extrusion molding band using a cooling drawer; ascertaining the size of the first extrusion molding band; repeating the above-mentioned steps by operating a second extruder if the size is satisfactory; repeating the above-mentioned steps by operating a third extruder if the two extrusion molding bands have no problem in their shape; bonding the two extrusion molding bands by a first bonder if the extrusion molding bands have no problem in their size and shape; bonding the two bonded extrusion molding bands with another extrusion molding band by using a second bonder if the extrusion molding bands have no problem in their appearance size; winding the three bonded extrusion molding bands at a predetermined angle if there is no problem; and bonding the three extrusion molding bands at the winding starting portions by using a third bonder.
For conventional flexible hoses, the design is complicated in the coupling structure of the extrusion molding bands, so that the working efficiency is lowered. Since the flexible hose is bonded at many points by bond or resin, it is problematic in reliably fix the extrusion molding bands, therefore for the conventional flexible hoses the product reliability is low. Since there exist many bonding points, the pitch of the conventional flexible hose is not uniform and the failure ratio is high. In addition, since the bonding portion has joint surfaces on both sides, the flexibility of the flexible hose is lowered and its thickness is large so that too much source material is consumed.
In addition, for the conventional flexible hose, the extrusion molding band can be molded only in one line. So, if two or more extrusion molding bands are extruded and elongated to fix the size in a sizing mold, the semicircular portion may be adhered to an upper portion of the electric wire embedding portion.